MR local coil with rotatable connection cable

Description

[0001] The invention relates to an MR local coil and a magnetic resonance apparatus.

[0002] In medical technology, magnetic resonance imaging (MRI), also known as magnetic resonance tomography (MRI), is characterized by high soft tissue contrast. This technique involves irradiating excitation pulses into an examination subject, usually a patient, using a magnetic resonance scanner. This triggers magnetic resonance signals in the patient. The magnetic resonance signals are received as measurement data by the scanner and used to reconstruct magnetic resonance images.

[0003] Magnetic resonance signals are often received using so-called local coils, which are also often called surface coils. Such MR local coils typically comprise one or more MR antennas and are placed in close proximity to the patient during an MRI examination.

[0004] A conventional MR local coil typically has an electrical connection to the magnetic resonance imaging device for power supply and signal transmission. This is typically achieved via a connecting cable. The connecting cable exits the local coil and connects to the magnetic resonance imaging device via a plug-in connector. Local coils are also placed on the patient for examination. They often cover part of the patient's body and are not limited to a fixed position relative to the patient, depending on the region to be examined. With MR local coils that can be flexibly positioned relative to the patient, the connecting cable can be routed differently depending on how the MR local coil is positioned on the patient.

[0005] The document JP H09 504 A discloses a two-part local coil with an upper and a lower part that are connected to each other by a hinge. The document US 2017 / 082705 A1 discloses a local coil with a connecting cable that is rotatably connected to the local coil. The document DE 10 2015 217325 A1 discloses a local coil arrangement that can be arranged directly on a patient table. The document JP 2008 154933 A discloses a local coil with a connecting cable for connecting the local coil to a magnetic resonance device. The document DE 10 2014 216077 A1 discloses a head coil that can be wirelessly connected to a magnetic resonance device by means of a direct connection.

[0006] The object of the present invention can be considered in particular to simplify the handling of an MR local coil, in particular the cable guide.

[0007] The problem is solved by the features of the independent claims. Advantageous embodiments are described in the dependent claims.

[0008] Accordingly, an MR local coil is proposed, comprising an antenna unit with at least one antenna for receiving and / or transmitting radio-frequency signals (HF signals for short), a connecting cable for connecting the MR local coil to a magnetic resonance device, and a flat, in particular ribbon-like, transmission element for transmitting, in particular electrical, energy and / or, in particular electrical and / or optical, signals between the connecting cable and the antenna unit. The transmission element is arranged, in particular coiled, at least partially spirally around a rotational axis. According to the invention, the connecting cable is designed to be rotated about the rotational axis relative to the antenna unit at a connection point of the connecting cable to the antenna unit.

[0009] According to the invention, the transmission element describes a spiral with at least half a turn, in particular at least one turn, in particular at least two turns around the rotation axis. In particular, the transmission element describes a helical curve within a plane or layer. In particular, the transmission element does not describe a screw, coil, and / or helix.

[0010] The transmission element is flat. In particular, it has a small thickness in the direction of the rotation axis. In particular, the transmission element has the shape of a band. This band preferably has a thickness that is at least three, in particular five, times less than the width of the band. This allows the transmission element to be easily formed into its spiral shape, in particular with little or no (mechanical) force.

[0011] The spiral arrangement of the transmission element describes a curve, in particular a helical line, that runs around the rotation axis and, particularly along the transmission element, moves away from or closer to the rotation axis (depending on the observer's perspective). Depending on the rotation state, the outer line of this curve can be at a smaller or greater distance from the rotation axis.

[0012] The transmitted RF signals are, for example, excitation signals, in particular excitation pulses, for exciting magnetic resonance signals. The received RF signals are, for example, magnetic resonance signals, which were generated in a patient's body using magnetic resonance.

[0013] The magnetic resonance device can, in particular, comprise a plug-in connector, in particular a socket, which can form a plug-in connection with a complementary plug-in connector of the connecting cable. The signals and / or energy can advantageously be transmitted via this plug-in connection.

[0014] The connecting cable and / or the transmission element preferably have electrical and / or optical conductors to transmit the energy and / or the signals.

[0015] Preferably, the connecting cable is detachably arranged on the (remaining) MR local coil, ie it can be removed without damaging the MR local coil.

[0016] Preferably, the rotation axis is arranged perpendicular to a surface, in particular a flat one, of the antenna unit. This surface preferably has a larger extension than any other surfaces of the MR local coil. According to the invention, the connecting cable can be rotated at the connection point to the antenna unit.

[0017] The antenna unit of freely positionable MR local coils (such as so-called body arrays) can be used in different relative positions on the patient, for example rotated by 0° or 90°. Thus, in contrast to an MR head coil, for example, which cannot usually be freely positioned, such an MR local coil often changes its position and distance from its socket on the magnetic resonance device. (The socket can be arranged, for example, on the patient table of the magnetic resonance device.) Because the connecting cable can now be rotated, the length of the connecting cable can be kept particularly short, which advantageously also reduces the weight of the MR local coil. Patient safety can also be increased if loops can be avoided on the patient by avoiding excessively long cables.

[0018] Furthermore, the rotatability allows for increased flexibility in handling the MR local coil, especially when placing it on the patient's body. Advantageously, the routing of the connecting cable, especially on the patient's body, can be designed to be more patient-friendly.

[0019] Another embodiment of the MR local coil provides that the transmission element comprises a flexible printed circuit board. The flexible printed circuit board can, in particular, be single- or multi-layered. It can preferably comprise an impedance-controlled layer, in particular a 50-ohm layer. The flexible printed circuit board preferably has a thickness of 0.1 to 2 mm, in particular 0.2 to 0.8 mm, in particular 0.4 mm. The normal of the (flat) surfaces of the printed circuit board is preferably aligned (essentially) perpendicular to the rotation axis.

[0020] Due to the thinness of the circuit board and / or its flexible material properties, the flexible circuit board can be easily wound around the rotation axis. Electrical conductor tracks, e.g., made of copper, are preferably applied to the flexible circuit board, through which signals and / or energy can be transmitted.

[0021] Another embodiment of the MR local coil provides for the transmission element to comprise a ribbon cable. The ribbon cable is preferably a multi-core cable in which the cores are arranged parallel to one another. Signals and / or energy can be transmitted via the cores. Advantageously, the ribbon cable can be easily wound spirally around the rotation axis.

[0022] A further embodiment of the MR local coil provides that the antenna unit comprises a plurality of antennas, in particular coil elements, wherein the transmission element comprises a plurality of adjacently arranged electrical and / or optical conductors for transmitting the signals of the plurality of antennas. These conductors can be designed, in particular, as conductor tracks on a flexible circuit board and / or as wires in a ribbon cable.

[0023] Each of the multiple antennas can be assigned to a channel, in particular a transmit channel and / or a receive channel. For example, if the antenna unit comprises 16 antennas, this can be referred to as a 16-channel MR local coil.

[0024] In addition to the conductors assigned to a specific channel, the transmission element may also comprise further conductors by means of which, for example, control information, coil identification data and / or electrical power can be transmitted.

[0025] Another embodiment of the MR local coil provides for the antenna unit to be particularly flat and / or flexible, particularly in the form of a blanket. MR local coils with such an antenna unit particularly benefit from the rotatability of the connecting cable, as these are often placed on the patient in very different orientations. Advantageously, the proposed connection of the connecting cable to the antenna unit eliminates the need to store an excess connecting cable, and the connecting cable does not deform the flexible antenna unit at the coil connection due to a suboptimal position.

[0026] A further embodiment of the MR local coil provides that the MR local coil comprises a housing with a first housing part and a second housing part, wherein the transmission element is arranged in the housing, wherein the second housing part is rotatable relative to the first housing part about the rotation axis.

[0027] Preferably, the first and second housing parts are rigid. Advantageously, the housing protects the transmission element from external influences.

[0028] Preferably, the second housing part is firmly connected to the antenna unit. In particular, the first housing part can in turn comprise several parts, and the antenna unit can comprise at least one cover layer that is clamped between said several parts of the first housing part.

[0029] A further embodiment of the MR local coil provides that the housing has a tongue and groove connection, wherein the second housing part is rotatable about the rotation axis relative to the first housing part by means of the tongue and groove connection.

[0030] Preferably, the tongue and groove connection is circular, with the rotation axis running through the center of the circle. For example, the first housing part has a projection that engages a recess (groove) in the second housing part (circumferential to the circle). This allows the second housing part to be stably guided relative to the first housing part during rotation about the rotation axis.

[0031] Another embodiment of the MR local coil provides that the housing has a stop that limits the possible rotation range around the rotation axis. This advantageously prevents overloading of the transmission element due to excessive rotation.

[0032] Another embodiment of the MR local coil provides that the second housing part comprises two parts that are connected to each other by means of screws and / or catches. This advantageously enables simple manufacture and / or assembly of the second housing part.

[0033] A further embodiment of the MR local coil provides that the MR local coil comprises a rigid-flex circuit board, wherein the transmission element is a flexible part of the rigid-flex circuit board, wherein the rigid-flex circuit board comprises a first rigid part which is connected to the first housing part by means of a first connection, wherein the rigid-flex circuit board comprises a second rigid part which is connected to the second housing part by means of a second connection.

[0034] Advantageously, the rigid-flex PCB is designed to ensure signal transmission even during multiple rotation cycles. In particular, the rigid-flex PCB is more space-efficient than a possible cable-stranded solution. Advantageously, the rigid-flex PCB can integrate other functions (position sensors, amplifiers, splitters, etc.) in addition to signal and / or power routing.

[0035] In particular, the flexible part is in the form of a band arranged spirally around the rotation axis. The first rigid part of the rigid-flex circuit board is arranged at a first end of the band, and the second rigid part of the rigid-flex circuit board is arranged at the other end, the second end, of the band.

[0036] The first connection and / or the second connection can in particular be fixed, ie the first and / or the second rigid part of the rigid-flex circuit board can be fixedly connected to the first or second housing part.

[0037] Another embodiment of the MR local coil provides for the first connection and / or the second connection to be detachable, e.g., by means of an intermediate plug connection. This advantageously enables easier repair of the MR local coil. For example, an intermediate plug connection on the second housing part allows for easier replacement of the connecting cable. Advantageously, the rigid-flex circuit board can be easily equipped with an intermediate plug connection, enabling quick and safe replacement of the connecting cable, for example, during assembly or a possible repair.

[0038] Another embodiment of the MR local coil provides that the transmission element has a first end and a second end, wherein the transmission element is angled at the first end and / or the second end, in particular by 90°. In particular, the flexible part of the rigid-flex circuit board has a first end and a second end, wherein the transmission element is angled at the first end and the second end, in particular by 90°.

[0039] Advantageously, this allows the transmission element to be routed out of a layer and / or plane of the spiral arrangement. This allows, for example, easier connection to the connecting cable and / or the antenna unit.

[0040] A further embodiment of the MR local coil provides that the first housing part and / or the second housing part comprises a gap which runs perpendicular to the axis of rotation, wherein the transmission element is passed through the gap.

[0041] In particular, the angled first and / or second end of the transmission element can be passed through the slot. Advantageously, the gap serves as a driver for the part of the transmission element arranged spirally around a rotational axis. In particular, the spiral is thereby tensioned or relaxed when the connecting cable rotates relative to the antenna unit.

[0042] A further embodiment of the MR local coil provides that the housing comprises a guide element, wherein at least the part of the transmission element arranged spirally around the rotation axis is arranged in the guide element and is guided by it.

[0043] Furthermore, a magnetic resonance device with at least one MR local coil as described above is proposed.

[0044] Further advantages, features, and details of the invention will become apparent from the exemplary embodiments described below and from the drawings. Corresponding parts are provided with the same reference numerals in all figures.

[0045] They show: Fig. 1 a magnetic resonance device with an MR local coil in a schematic representation, Fig. 2-3 an arrangement with a transmission element for transmitting energy and / or signals between a connecting cable and an antenna unit of the MR local coil, Fig. 4 a transmission element in a rolled-out state, Fig. 5 a transmission element in spiral form in a first rotation state, Fig. 6 a transmission element in spiral form to a second rotation state, Fig. 7 an element of the arrangement with a gap in which the transmission element is passed, Fig. 8 an intermediate housing to accommodate the transmission element.

[0046] In Fig. 1 1 schematically shows a magnetic resonance apparatus 10 with an MR local coil 100 arranged on a patient 15. The magnetic resonance apparatus 10 comprises a magnet unit 11 having a main magnet 12 for generating a strong and, in particular, temporally constant main magnetic field 13. Furthermore, the magnetic resonance apparatus 10 comprises a patient receiving area 14 for receiving the patient 15. In the present exemplary embodiment, the patient receiving area 14 is cylindrical and is surrounded in a circumferential direction by the magnet unit 11. In principle, however, a different design of the patient receiving area 14 is conceivable at any time. The patient 15 can be pushed into the patient receiving area 14 by means of a patient support device 16 of the magnetic resonance apparatus 10.For this purpose, the patient support device 16 has a patient table 17 which is designed to be movable within the patient receiving area 14.

[0047] The magnet unit 11 further comprises a gradient coil unit 18 for generating magnetic field gradients used for spatial encoding during imaging. The gradient coil unit 18 is controlled by a gradient control unit 19 of the magnetic resonance device 10. The magnet unit 11 further comprises a radio-frequency antenna unit 20, which in the present exemplary embodiment is designed as a body coil permanently integrated into the magnetic resonance device 10. The radio-frequency antenna unit 20 is controlled by a radio-frequency antenna control unit 21 of the magnetic resonance device 10 and radiates magnetic resonance sequences in the form of radio-frequency (RF) signals into an examination space, which is essentially formed by a patient receiving area 14 of the magnetic resonance device 10. As a result, the main magnetic field 13 generated by the main magnet 12 excites atomic nuclei.By relaxing the excited atomic nuclei, magnetic resonance signals, which in turn are RF signals, are generated. The radio-frequency antenna unit 20 is configured to receive the magnetic resonance signals. Furthermore, the MR local coil comprises an antenna unit 120 with antennas that are also configured to receive and / or transmit RF signals. Advantageously, the antenna unit 120 is flexible, for example, like a blanket, so that the antennas can be mounted particularly close to the body of the patient 15.

[0048] The magnetic resonance apparatus 10 has a system control unit 22 for controlling the main magnet 12, the gradient control unit 19, and the radio-frequency antenna control unit 21. The system control unit 22 centrally controls the magnetic resonance apparatus 10, such as performing a predetermined imaging gradient echo sequence. Furthermore, the system control unit 22 includes an evaluation unit (not shown in detail) for evaluating the magnetic resonance signals acquired during the magnetic resonance examination. Furthermore, the magnetic resonance apparatus 10 includes a user interface 23 connected to the system control unit 22. Control information, such as imaging parameters, as well as reconstructed magnetic resonance images, can be displayed on a display unit 24, for example, on at least one monitor, of the user interface 23 for medical personnel.Furthermore, the user interface 23 has an input unit 25 by means of which information and / or parameters can be entered by the medical operating personnel during a measurement process.

[0049] The MR local coil 100 is connected via a connecting cable 116 to a slot of the magnetic resonance device 10 arranged on the patient table 17, via which slot signals and / or energy can be transmitted from and / or to the radio-frequency antenna control unit 21.

[0050] At the connection point between the connecting cable 116 and the antenna unit 120 of the MR local coil, there is a flat transmission element 107 for transmitting energy and / or signals between the connecting cable 116 and the antenna unit 120, which is illustrated in detail in the following figures. In particular, an exemplary embodiment is shown of how a mechanical and electrical connection from the connecting cable to the antenna unit 120 of the MR local coil 100 can be designed to be rotatable.

[0051] As in the Fig. 2 and 3 As shown, the arrangement consists of several housing parts that can be rotated relative to one another. A first housing part 101 is fixedly connected to the local coil. For this purpose, the first housing part comprises, for example, two parts between which a cover layer of the antenna unit 120 can be clamped.

[0052] A wide housing part comprising two parts 102, 103 is rotatably mounted to the first housing part 101. The pivot joint is implemented via a tongue and groove connection 104. For easier assembly, the first housing is divided into two parts 102 and 103 and is connected to each other, for example, via screws or catches. The angle of rotation can be limited by a stop between the rotating parts, i.e., the first housing part 101 and the second housing part 102, 103.

[0053] Contacting is made via a rigid-flex circuit board 105, which is Fig. 4 The rigid-flex circuit board 105 comprises two rigid parts 106, 108 and a flexible part in the form of a flexible circuit board, which forms a flat transmission element 107.

[0054] The rigid part 106 is firmly connected to the first housing part 101. The transmission element 107 forms a spiral by bending twice at the points AP and rolling up, which is tensioned like a spiral spring by the rotation, see Fig. 6 , or relax, see Fig. 5 , can. The transmission element 107 is thus partially arranged spirally around a rotation axis R.

[0055] The length of the transmission element 107 and the minimum winding diameter in the form of a limiting element 112, which prevents the conductor tracks of the transmission element 107 from breaking due to the constant tensioning and relaxing of the spiral, define the achievable rotation angle. The longer the flexible part, the greater the achievable rotation angle of the connecting cable 116 to the antenna unit 120 of the MR local coil.

[0056] A printed circuit board 114 is arranged on the second housing part (102, 103), which, together with the second housing part (102, 103), is rotatable relative to the first housing part (101). The rigid part 108 of the rigid-flex printed circuit board 105 comprises a plug 113 (or a socket) that is plugged into a socket 115 (or a plug) on ​​the printed circuit board 114, thus forming a detachable connection. This intermediate plug connection enables the connecting cable 116 of the MR local coil 100 to be replaced. It is also conceivable to dispense with this intermediate plug connection; in this case, the rigid part 108 functionally corresponds to the rotatable printed circuit board 114. The connecting cable 116, which connects the MR local coil 100 to the magnetic resonance device 10, is connected to this rotatable printed circuit board 114, for example, by means of a soldered connection.The rotatable circuit board 114 allows for more delicate assembly and is easy to install during the final assembly of the MR local coil 100 via the intermediate plug connection.

[0057] As in Fig. 7 As can be seen, the rotatable circuit board 114 has recesses 117, which form a positive connection with pins in the parts 102 and 103 of the second housing part. This positive connection acts as a driver between the circuit board 114 and the second housing part 102, 103. The circuit board 114 has a gap 119. The angled end of the transmission element 107 with the rigid part 108 is inserted into this gap 119 and thus reaches the plug 113 of the intermediate plug connection. This gap 119 serves as a driver of the spiral-shaped transmission element 107, which thus tensions and relaxes when the circuit board 114 rotates, see Fig. 5 und 6 . An intermediate housing, as used in Fig. 8The guide element 118, shown in FIG. 1, serves as a guide element 118, in which the spiral-shaped transmission element 107 can be tensioned and released; it also serves to guide it. It is firmly connected to the first housing part 101.

[0058] The rotatability ideally always places the output of the connecting cable 116 from the MR local coil 100 in the optimal position relative to the slot 26 of the magnetic resonance device. This improves handling and optimizes the position of the connecting cable 116 on the patient 15. The rotatable connecting cable 116 allows the required cable length to be shortened. This results in, in particular, fewer sheath wave barriers being required for the connecting cable 116. This increases the flexibility of the connecting cable 116 (the sheath wave barrier area stiffens the connecting cable 116) and reduces its weight.

[0059] Finally, it should be noted once again that the MR local coil and the magnetic resonance device described in detail above are merely exemplary embodiments that can be modified in a variety of ways by those skilled in the art without departing from the scope of the invention, which is defined by the claims. Furthermore, the use of the indefinite articles "a" or "an" does not exclude the possibility that the respective features may be present in multiple instances. Likewise, the term "unit" does not exclude the possibility that the respective components consist of several interacting subcomponents, which may also be spatially distributed.

Claims

1. MR local coil comprising - an antenna unit (120) having at least one antenna for receiving and / or transmitting HF signals, - a connection cable (116) for connecting the MR local coil (100) to a magnetic resonance apparatus (10), - a flat transmission element (107) for transmitting energy and / or signals between the connection cable (116) and the antenna unit (120), wherein the connection cable is designed so as to be rotated on a connecting site of the connection cable to the antenna unit about an axis of rotation relative to the antenna unit, characterised in that the transmission element (107) is at least in part arranged about the axis of rotation (R) in a spiral manner, wherein the transmission element describes a coil having at least one half winding about the axis of rotation.

2. MR local coil according to claim 1, wherein the transmission element (107) comprises a flexible circuit board and / or a flat ribbon cable.

3. MR local coil according to one of the preceding claims, wherein the antenna unit (120) comprises multiple antennas, wherein the transmission element (107) comprises multiple electrical and / or optical conductors, which are arranged adjacent to one another, in order to transmit the signals of the multiple antennas.

4. MR local coil according to one of the preceding claims, wherein the antenna unit (120) is designed as flat.

5. MR local coil according to one of the preceding claims, wherein the antenna unit (120) is designed as flexible.

6. MR local coil according to one of the preceding claims, wherein the MR local coil (100) comprises a housing having a first housing part (101) and a second housing part (102, 103), wherein the transmission element (107) is arranged in the housing, wherein the second housing part (102, 103) can be rotated relative to the first housing part (101) about the axis of rotation (R).

7. MR local coil according to claim 6, wherein the housing comprises a tongue and groove connection (104), wherein the second housing part (102, 103) is guided relative to the first housing part (101) by means of the tongue and groove connection (104) in a rotatable manner about the axis of rotation (R).

8. MR local coil according to one of claims 6 or 7, wherein the housing has a stop and / or a limiting element (112), which is arranged within the spiral-shaped arrangement, and the stop limits a possible rotational range about the axis of rotation (R).

9. MR local coil according to one of claims 6 to 8, wherein the MR local coil (100) comprises a rigid flexible circuit board (105), wherein the transmission element is a flexible part of the rigid flexible circuit board (105), wherein the rigid flexible circuit board (105) comprises a first rigid part that is connected by means of a first connection to the first housing part (101), wherein the rigid flexible circuit board (105) comprises a second rigid part that is connected by means of a second connection to the second housing part.

10. MR local coil according to claim 9, wherein the first connection and / or the second connection are designed in a detachable manner.

11. MR local coil according to one of claims 6 to 10, wherein the first housing part (101) and / or the second housing part (102) comprises a gap (119) that extends perpendicular to the axis of rotation, wherein the transmission element (107) is guided through the gap (119).

12. MR local coil according to one of claims 6 to 11, wherein the housing comprises a guiding element (118), wherein at least the part of the transmission element (107), which is arranged in a spiral manner about the axis of rotation (R), is arranged in the guiding element (118) and is guided by said guiding element.

13. MR local coil according to one of the preceding claims, wherein the spiral-shaped arrangement of the transmission element (107) has a first end and a second end around the axis of rotation (R), wherein the transmission element (107) is angled at the first end and / or at the second end, in particular by 90°.

14. MR local coil according to claim 13, wherein the transmission element (107) is angled at the first end and / or the second end by 90°.

15. Magnetic resonance apparatus (10) having at least one MR local coil (100) according to one of claims 1 to 14.